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研究了用氨作为络合剂的氨—柠檬酸盐镀液电沉积制取Ni-Mo非晶合金镀层,以及镀层的耐蚀性,热处理对镀层的晶化和硬度的影响。含NiSO_40.13～0.18mol/L和Na_2MO_4 0.08～0.13mol/L,其金属离子(Ni~(2+)+Mo~(6+))总和为0.26 mol/L的溶液中,加入络合剂柠檬酸钠0.32mol/L和氨0.53mol/L,PH为9的镀液,在30℃,电流密度为8～20A/dm~2条件下,电沉积得到Ni-Mo非晶合金镀层。对镀液进行电解老化处理后,电沉积镀层中的Mo含量可高达37wt％,同时阴极电流效率增大,并且消除了镀层的起皮和裂纹。Mo含量在28wt％以上的镀层呈非晶结构。在30℃的1N H_2SO_4和1N HCl溶液中,进行了镀层的电化学测试和浸渍试验,结果表明:Ni-Mo非晶合金镀层,较之晶态合金镀层,具较强的自钝化能力和低的腐蚀速率,在上述腐蚀介质中的耐蚀性能优于304不锈钢。测定了经不同温度热处理后镀层的结构和显微硬度。Ni-Mo非晶合金的晶化温度为500～550℃,经600～650℃热处理后,伴随着Ni_4Mo和Ni_3Mo金属间化合物的析出,镀层的硬度可高达1100～1320Hv。
The effects of corrosion resistance and heat treatment on the crystallization and hardness of Ni-Mo amorphous alloy coatings prepared by electrodeposition of ammonia-citrate bath with ammonia as complexing agent were investigated. The solution containing NiSO_ (40.13 ~ 0.18mol / L) and Na_2MO_4 (0.08 ~ 0.13mol / L) and the total metal ions (Ni ~ (2 +) + Mo ~ (6+) Sodium citrate 0.32mol / L and ammonia 0.53mol / L, PH 9 plating solution, at 30 ℃, the current density of 8 ~ 20A / dm ~ 2 conditions, the electrodeposited Ni-Mo amorphous alloy coating. After electrolytic aging of the bath, the content of Mo in the electrodeposition coating can reach as high as 37 wt%, while the cathode current efficiency increases, and the peeling and cracking of the coating are eliminated. The coating having a Mo content of 28 wt% or more has an amorphous structure. The electrochemical tests and impregnation tests of the coatings were carried out in 1N H 2 SO 4 and 1N HCl solutions at 30 ℃. The results show that the Ni-Mo amorphous alloy coating has better self-passivation ability than the crystalline alloy coating and Low corrosion rate, corrosion resistance in the above corrosive medium is better than 304 stainless steel. The structure and microhardness of the coating after heat treatment at different temperatures were measured. Ni-Mo amorphous alloy crystallization temperature of 500 ~ 550 ℃, after 600 ~ 650 ℃ heat treatment, along with the precipitation of Ni_4Mo and Ni_3Mo intermetallic compounds, the hardness of the coating up to 1100 ~ 1320Hv.